<h2>DESCRIPTION</h2>

<em>r.topmodel</em> simulates TOPMODEL which is a physically based
hydrologic model.

<h3>Parameters description</h3>

<dl>
<dt><b>parameters</b></dt>
<dd>
This file contains TOPMODEL parameters that describe the study area. Any lines
starting with a # sign or empty lines are ignored.
<div class="code"><pre>
# Subcatchment name
Subcatchment 1

################################################################################
# A [m^2]: Total subcatchment area
3.31697E+07

################################################################################
# qs0 [m/h]: Initial subsurface flow per unit area
#		"The first streamflow input is assumed to represent
#		 only the subsurface flow contribution in the watershed."
#								- Liaw (1988)
0.000075

# lnTe [ln(m^2/h)]: Areal average of the soil surface transmissivity
4.

# m [m]: Parameter controlling the decline rate of transmissivity
# See Beven and Kirkby (1979)
0.0125

# Sr0 [m]: Initial root zone storage deficit
0.0025

# Srmax [m]: Maximum root zone storage deficit
0.041

# td [h]: Unsaturated zone time delay per unit storage deficit if greater than 0
#  OR
# -alpha: Effective vertical hydraulic gradient if not greater than 0.
#
# For example, -10 means alpha=10.
60.

# vch [m/h]: Main channel routing velocity
20000.

# vr [m/h]: Internal subcatchment routing velocity
10000.

################################################################################
# infex: Calculate infiltration excess if not zero (integer)
0

# K0 [m/h]: Surface hydraulic conductivity
2.

# psi [m]: Wetting front suction
0.1

# dtheta: Water content change across the wetting front
0.1

################################################################################
# d [m]: Distance from the catchment outlet
#		The first value should be the mainstream distance from
#		the subcatchment outlet to the catchment outlet.
# Ad_r:  Cumulative area ratio of subcatchment (0.0 to 1.0)
#		The first and last values should be 0 and 1, respectively.

#   d  Ad_r
    0   0.0
 1000   0.2
 2000   0.4
 3000   0.6
 4000   0.8
 5000   1.0
</pre></div>
</dd>

<dt><b>input</b><dt>
<dd>
This file contains observed weather data.
<div class="code"><pre>
# dt [h]: Time step
24

################################################################################
# R [m/dt]:  Rainfall
# Ep [m/dt]: Potential evapotranspiration

# R             Ep
0.000033        0.000000
0.000053        0.011938
0.004821        0.000000
.
.
.
</pre></div>
</dd>

<dt><b>timestep</b></dt>
<dd>
If a time step is specified, output will be generated for the specific time
step in addition to the summary and total flows at the outlet. This parameter
can be combined with <b>topidxclass</b> to specify a time step and topographic index
class at the same time. If no <b>topidxclass</b> is given, output will be generated
for all the topographic index classes.
</dd>

<dt><b>toptopidxclass</b></dt>
<dd>
If a topographic index class is specified, output will be generated for the
given topographic index class. This parameter can be combined with <b>timestep</b>. If
no <b>timestep</b> is given, output will be generated for all the time steps.
</dd>

<dt><b>topidx</b>, <b>ntoptopidxclasses</b>, <b>outtoptopidxstats</b></dt>
<dd>
The <b>topidx</b> map can optionally be used for creating a new topographic
index statistics file. This map has to be already clipped to the catchment
boundary. The entire range of topographic index values will be divided into
<b>ntoptopidxclasses</b> and the area ratio of each class will be reported in the
<b>outtoptopidxstats</b> file. These three parameters can be omitted unless a new
<b>topidxstats</b> file needs to be created.
</dd>
</dl>


<h2>REFERENCES</h2>

<ul>
  <li>Beven, K. J., 1984. Infiltration into a class of vertically non-uniform
  soils. Hydrological Sciences Journal 29 (4), 425-434.

  <li>Beven, K. J., Kirkby, M. J., 1979. A physically based, variable
  contributing area model of basin hydrology. Hydrological Sciences Bulletin 24
  (1), 43-69.

  <li>Beven K. J., R. Lamb, P. Quinn, R. Romanowicz, and J. Freer, 1995.
  TOPMODEL, in V.P. Singh (Ed.). Computer Models of Watershed Hydrology. Water
  Resources Publications.

  <li>Cho, H., 2000. GIS Hydrological Modeling System by Using Programming
  Interface of GRASS. Master's Thesis, Department of Civil Engineering,
  Kyungpook National University, South Korea.

  <li>Liaw, S. C., 1988. Streamflow Simulation Using a Physically Based
  Hydrologic Model in Humid Forested Watersheds. Dissertation, Colorado State
  University, CO. p163.

  <li>Morel-Seytoux, H. J., Khanji, J., 1974. Derivation of an equation of
  infiltration. Water Resources Research 10 (4), 795-800.
</ul>


<h2>SEE ALSO</h2>
<em>
<a href="r.fill.dir.html">r.fill.dir</a>,
<a href="r.mapcalc.html">r.mapcalc</a>,
<a href="r.topidx.html">r.topidx</a>
</em>
<br>
<a href="http://idea.isnew.info/r.topmodel.html">How to run r.topmodel</a>


<h2>AUTHORS</h2>

<a href="mailto:grass4u@gmail com">Huidae Cho</a>,
Hydro Laboratory, Kyungpook National University, South Korea
<p>
Based on TMOD9502.FOR by Keith Beven.

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